Mendel crossed a pea plant having inflated green pod with a constricted yellow pod.
$(a)$ What type of a cross is it?
$(b)$ What type of plants are obtained in $F_{1}$ generation?
$(c)$ In $F_{2}$ generation the phenotype ratio is $9:3:3:1$. State the rule for the inheritance of traits observed by Mendel.

(N/A) This is a Dihybrid cross because it involves the study of the inheritance of two pairs of contrasting traits (pod shape and pod color).
$(b)$ In the $F_{1}$ generation,all plants obtained have inflated and green pods,as these are the dominant traits.
$(c)$ The rule observed is the Law of Independent Assortment. It states that when two pairs of traits are combined in a hybrid,segregation of one pair of characters is independent of the other pair of characters at the time of gamete formation.